First - does it need to be a multi-page form. What sottwell is doing is mimicking a multi-page process, while actually only using one page (it’s more complex than that, but this is the gist). You could use an accordion feature to show or hide form elements, to make it seem less long.
If you _must_ paginate it, then the simplest solution in Revolution is as smooth-graphics says - chain the pages using FormIt and FormItRetriever
Resource 1 - FormIt - redirect to resource 2 on completion
Resource 2 - FormItRetriever - retrieve all the variables into hidden fields in a new FormIt form - redirect to resource 3 on completion
Resource 3 - FormItRetriever - retrieve all the variables from both resources 1 and 2, into hidden fields if you want to add yet more fields (with another FormIt).
You don’t _have_ to save to a database - you could just email the results at the end of the chain, but it would probably make more sense to store it - in which case you will need to write a custom snippet to run as a ’hook’ on your last FormIt, that saves the data to a custom table. In order to do that, you will need to create a MODx object for that table - there is a tutorial on that here :
http://rtfm.modx.com/display/revolution20/Using+Custom+Database+Tables+in+your+3rd+Party+Components
It sounds more complicated than it actually is, you just need to get used to it.